Lately, for both Ebola virus and Middle East respiratory syndrome coronavirus, there have been instances where I've been reminded that one must not rely on the growth of an infectious virus from a sample to be sure that there is virus in that sample.

Two studies have now found antibodies from Middle East respiratory syndrome coronavirus (MERS-CoV)-like coronaviruses in dromedary camels (DCs). The "like" bit reflects that unless we have some sequence, we can't say for certain that the virus that infected those camels in the past, causing them to respond with these antibodies, was a MERS-CoV variant. The virus(es) may have been a different camel CoV that just so happens to share some antigens and is detected by MERS-CoV-"specific" antibody detection tests. The old story of "we don't know what we don't know" can perhaps be extended here to "we can't validate a test against viruses we haven't found yet". Or that may just be too nerdy.